Atropine

• ANTICHOLINERGIC
• Prevent/trt bardycardia, hypersalivation
• Competetively antagonizes ACh
  • decreases vagal tone
  Pros-
  
  • Crosses the BBB
    
• Cons-
  
  • May cause bradycardia, AV block, ventricular arrhythmias
  • Crosses the placenta!
  • Horse: colic
  • Ruminant: bloat
  • Dog: depression
    

Glycopyrrolate

• ANTICHOLINERGIC
• Prevent/trt bardycardia, hypersalivation
• Competetively antagonizes ACh
  • decreases vagal tone
    
• Cons-
  
  • May cause bradycardia, AV block, ventricular arrhythmias
  • Does NOT cross the BBB
    
  • Horse: colic
  • Ruminant: bloat
  • Dog: depression
    

Acepromazine

• PHENOTHIAZINE derivative
• Use: sedative/tranq; routinely used as preanesthetic
• Alpha1 blockade => vasodilation, hypotension
• Pros
  • Lasts for hours, antiemetic, mm. relaxant
• Cons
  • NO analgesia, slow onset of sedation
  • Permanent penile paralysis in stalions
  • Hypotension (don't use in Boxers)
  • Metabolized by the liver

Droperidol

• BUTYROPHENONE
• Use = sedative/tranq
• Alpha1 blockade => vasodilation and hypotension
• Pros
  • mm. relaxation, antiemetic, antiarrhythmic, antihistaminic
• Cons
  • hypotension, hypothermia, inhibit platelet aggregation, NO ANALGESIA, may lower seizure threshold
  • NOT commonly used in vet med

Azaperone

• BUTYROPHENONE
• Use = sedative/tranq
• Alpha1 blockade => vasodilation and hypotension
• Pros
  • mm. relaxation, antiemetic, antiarrhythmic, antihistaminic
• Cons
  • hypotension, hypothermia, inhibit platelet aggregation, NO ANALGESIA, may lower seizure threshold
  • NOT commonly used in vet med

Xylazine, Detomidine

• ALPHA2 AGONIST
• Use = sedatives/tranqs and preanesthetic
• Action
  • Alpha2 agonist => mm relaxation
  • Acts centrally => sedation and analgesia
  • Peripheral vasoconstriction, increased BP and HR
• Pros
  • reduces the dose of anesthetics required; reversible; analgesia
• Cons
  • 1st or 2nd degree heart block; severe bradycardia; decreased HR and CO; hypertension, resp depression; vomiting; bloat; ileus

Diazepam

• BENZODIAZEPINE
• Use = reliable preanesthetic in foals, sm.ruminants, rodents and potbelly pigs
  • Preanesthetic and induction
• Action = enhanced CNS inhibitory NTs; causes mm. relaxation
• Pros
  • minimal CV/pulm effects in SA
• Cons
  • NO ANALGESIA; poorly water soluble (no IM); may cause nervousness in SA
• Reversed w/ IM fumazenil

Midazolam

• BENZODIAZEPINE
• Use = reliable preanesthetic in foals, sm.ruminants, rodents and potbelly pigs
  • Preanesthetic and induction
    
• Action = enhanced CNS inhibitory NTs; causes mm. relaxation
• Pros
  • minimal CV/pulm effects in SA; water soluble (IM=okay)
    
• Cons
  • NO ANALGESIA; may cause nervousness in SA
• Reversed w/ IM fumazenil
  

Zolazopam

• BENZODIAZEPINE
• Use = reliable preanesthetic in foals, sm.ruminants, rodents and potbelly pigs
  • Preanesthetic and induction
    
• Action = enhanced CNS inhibitory NTs; causes mm. relaxation
• Pros
  • minimal CV/pulm effects in SA; water soluble (IM=okay)
    
• Cons
  • NO ANALGESIA; may cause nervousness in SA
• Reversed w/ IM fumazenil
  

Butorphanol

• OPIOID
• Uses = analgesic; CNS depression
• Kappa agonist
• Pros
  • Good analgesic; CV sparing; reduces dose of subsequent anesthetic
  • Great sedation in dogs; short acting
• Cons
  • Resp depression; causes excitement in cats and horses; can cause histamine release, ADH release
• Will reverse activity of mu agonists

Buprenorphine

• OPIOID
• Uses = analgesic; CNS depression
• Partial mu agonist
• Pros
  • Good analgesic; CV sparing; reduces dose of subsequent anesthetic
  • Great sedation in dogs; long acting
• Cons
  • Resp depression; causes excitement in cats and horses; can cause histamine release, ADH release
• Difficult to reverse with Naloxone

Hydromorphone

• OPIOID
• Uses = analgesic; CNS depression
• Pure mu agonist
• Pros
  • STRONG analgesic; CV sparing; reduces dose of subsequent anesthetic
  • Great sedation in dogs; medium duration
• Cons
  • Resp depression; causes excitement in cats and horses; can cause histamine release, ADH release
  • Cats = HYPERthermia

Morphine

• OPIOID
• Uses = analgesic; CNS depression
• Pure mu agonist
• Pros
  • STRONG analgesic; CV sparing; reduces dose of subsequent anesthetic
  • Great sedation in dogs; medium duration
• Cons
  • Resp depression; causes excitement in cats and horses; can cause histamine release, ADH release
• Will reverse activity of mu agonists

Fentanyl

• OPIOID
• Uses = analgesic; CNS depression
• Pure mu agonist
• Pros
  • STRONG analgesic; CV sparing; reduces dose of subsequent anesthetic
  • Great sedation in dogs; VERY short acting
• Cons
  • Resp depression; causes excitement in cats and horses; can cause histamine release, ADH release
• Will reverse activity of mu agonists

Methohexitol

• BARBITUATE
• Use= injectable anesthetic, sedative, anxiolytic, relaxant, anticonvulsant
  • Induction
• Causes GABA receptors to go w/out GABA
• Pros
  • high quality anesthesia; well-rounded
• Cons
  • be careful of OD (coma)
  • *NO reversal agent; not as smooth recovery

Thiopental

• BARBITUATE
• Use= induction agent
• CNS depression by interacting with GABA receptors
• Pros
  • in SA, use w/ Propofol to induce (esp with head trauma); well rounded
• Cons
  • Ultra-short acting; resp depression; very alkaline; initial spike in BP/HR and then CV depression; crosses placenta; DEA level 3 controlled substance; metabolized in the liver; NO reversal; careful of OD!

Ketamine

• DISSOCIATIVE ANESTHETIC
• Activation of the cortex, depression of the thalamoneocortical system; increased sympathetic tone
• Pros
  • profound analgesia; increases HR, BP, CO
• Cons
  • CNS excitation instead of depression - seizures
  • hypersalivation; poor visceral analgesia; mm. rigidity; apnea
  • NO reversal agen; eyes stay open/dilated

Tiletamine

• DISSOCIATIVE ANESTHETIC
• Activation of the cortex, depression of the thalamoneocortical system; increased sympathetic tone
• Pros
  • profound analgesia; increases HR, BP, CO
• Cons
  • lack of control of anesthetic depth and duration
  • CNS excitation - seizures, mm.rigidity
  • poor visceral analgesia
  Sold in a 1:1 combo with Tiletamine

Propofol

• NON-barbituate
• Used for induction and anesthesia
• Acts on GABA receptors => CNS depression
• Pros
  • Rapid acting; ultra short; rapid extra-hep metabolism 
  • no cardiac arrhythmias
• Cons
  • Expensive; must be used within 6 hours of opening
  • No reversal agent
  • CV/Pul depression

Guaifensin

• NON-barbituate
• Used for induction and anesthesia
• Central acting mm. relaxant - - blocks impulses at SpCord/brain stem
• Pros
  • Minimal CV effects
• Cons
  • No reversal agent
  • Irritating to tissues
  • Decreases resp tidal volume

Etomidate

• NON-barbituate
• Used for induction and anesthesia
• Acts on GABA receptors => CNS depression
• Pros
  • Rapid acting; ultra short; rapid extra-hep metabolism 
  • no cardiac arrhythmias
  • Minimal CV effects
• Con
  • Lack of control of anesthetic depth/duration
  • Expensive; IV ONLY; depresses adrenocorticotropic functions

Alfaxalone

• NON-barbituate
• Used for induction and anesthesia - NOT avail. in US
• Acts on GABA receptors => CNS depression
• Pros
  • Rapid acting; ultra short; rapid extra-hep metabolism 
  • no cardiac arrhythmias
  • IM or IV = not painful
• Cons
  • lack of control of anesthetic depth

Pentobarbital

• BARBITUATE
• Used for induction and anesthesia
• Acts on GABA receptors => CNS depression
• Pros
  • Rapid acting
  • 45-90 minute duration
  • no cardiac arrhythmias

Phenobarbital

• BARBITUATE
• Used for induction and anesthesia
• Acts on GABA receptors => CNS depression
• Pros
  • Rapid acting
  • 8-12hr duration
  • no cardiac arrhythmias

General info on inhalant anesthetics

• Iso, Sevo, Des, NO
• Produces general anesthesia (unconciousness, analgesia, hyporeflexia) in ALL species
• MAC = min alveolar [] (ED50)
• Pros
  • Allows controlled dose; eliminated by lungs
  • rapid induction and recovery
  • mm. relaxation
• Cons
  • Must be given with O2; NOT analgesic at low doses
  • can cause hypotension and resp depression
• 1Tc=63%; 2Tc= 86%; 3Tc=95; 4Tc=98%

Isoflurane

• INHALANT ANESTHETIC
• MACs
  • 1.3% (dog), 1.63% (cat), 1.31% (horse)
• Pros
  • All species = rapid induction and recovery
  • Easy on kidneys (decrease RBF and GFR)
  • No hepatocellular damage; inexpensive
• Cons
  • Resp depression (decreases tidal vol, resp rate; increases PaCOs)
  • CV depression: decreased CO and BP; vasodilation
  • produces Carbon monoxide in absorbent

Sevoflurane

• INHALANT ANESTHETIC
• MACs
  • 2.34% (dog), 2.58% (cat), 2.34% (horse)
• Pros
  • All species = rapid induction and recovery
  • Better odor
    
• Cons
  • Resp depression (decreases tidal vol, resp rate; increases PaCOs)
  • CV depression: decreased CO and BP; vasodilation
  • produces "Compound A" in absorbent
  • can be nephrotoxic
    

Nitrous oxide

• INHALANT ANESTHETIC
• MACs
  • 200% (dog), 255% (cat), 190% (horse)
• Pros
  • All species = rapid induction and recovery
  • Minimal CV effects; enhanced takeup of 2nd gas
    
• Cons
  • Low potency (MAC = 200%)
  • diffusion hypoxia if recovered on room air
  • diffuses into closed gas spaces
    

Desflurane

• INHALANT ANESTHETIC
• MACs
  • 7.2% (dog), 9.8% (cat), 7.23% (horse)
• Pros
  • All species = rapid induction and recovery
  • Lower B/G = faster; Lower fate/B coefficient = quicker recovery
    
• Cons
  • requires expensive equipment
  • CV depression